Field of the Invention
Exemplary embodiments of the present invention relate to an apparatus and method for reactor power control of a steam turbine power generation system, and more particularly, to an apparatus and method for reactor power control of a steam turbine power generation system, capable of following a power change request by regulating and controlling a flow rate of steam introduced into a turbine.
Description of the Related Art
Power generation systems using a steam turbine are used for a thermal power plant or a nuclear power plant.
Among them, a nuclear power generation system will be illustratively described in more detail with reference to FIG. 1. The nuclear power generation system may include a reactor 7, turbines 17 and 19, a condenser 21, and feed water heaters 22 and 24.
The reactor 7 includes a core in which a plurality of fuel rods and a control rod for controlling reactivity of the core are arranged, and generates steam supplied to the turbines 17 and 18 to be described later. The control rod adjusts power of the reactor, namely core power.
Steam generated by the reactor 7 is supplied to a main steam pipe 14 connected to the reactor 7. The steam supplied to the main steam pipe 14 is supplied to a high-pressure turbine 17 via a main steam pipe control valve 16 provided on the main steam pipe 14. The main steam pipe control valve 16 regulates an amount of the steam supplied to the high-pressure turbine 17.
The seam supplied to the high-pressure turbine 17 is supplied to a low-pressure turbine 19 via a moisture separator reheater 18. The low-pressure turbine 19 is connected to a generator 20.
The condenser 21 for condensing the steam discharged from the low-pressure turbine 19 is installed at an outlet of the low-pressure turbine 19. A low-pressure feed water heater 22, a feed water pump 23, and a high-pressure feed water heater 24 are installed downstream from the condenser 21. A feed water pipe 15 is connected to an outlet of the high-pressure feed water heater 24.
The feed water pipe 15 joined from the condenser 21 to the reactor 7 is provided downstream from the condenser 21. The low-pressure feed water heater 22 for heating feed water supplied from the condenser 21 and the high-pressure feed water 24 for pressurizing feed water to supply the pressurized feed water to the reactor are sequentially disposed on the feed water pipe 15.
In the nuclear power generation system described above, steam generated by the reactor is supplied to the high-pressure and low-pressure turbines through the main steam pipe and the turbines are rotated by the steam to rotate the generator connected thereto.
The steam discharged from the low-pressure turbine is condensed through the condenser, and condensed condensate is heated by the multiple feed water heaters installed on the feed water pipe so as to be supplied back to the reactor through the feed water pipe.
Meanwhile, consumption of electric power greatly varies according to seasons, weekdays and weekends, day and night, etc. An electric power system allows an amount of power generation and power consumption to be balanced so that a voltage and a power system frequency are stably maintained.
Power adjustment of the electric power system as a whole is mainly performed on thermal power generation or hydraulic power generation. However, power control is also needed on nuclear power generation as the percentage of nuclear power generation is increased recently.
Conventionally, it is apprehended that gaseous radioactive fission products (xenon, iodine, etc) leak into reactor cooling water when a fuel cladding conduit is cracked by a thermal change according to a power change. Therefore, the nuclear power generation system operates at uniform power.
However, in recent years, in the nuclear power generation system, measures such as an improvement of the cladding conduit are taken to resolve the above apprehension, and electric power companies, manufacture companies, and research institutes perform research, test, and the like on power adjustment operation. In addition, the nuclear power generation system is designed such that power may be changed, that is, power may be adjusted by operation thereof.
When consumption of electric power exceeds production in the electric power system, the speed of a generator is decreased and a power system frequency is lowered. When the production exceeds the consumption, the speed of the generator is increased and the power system frequency is raised. The power control of the power generation system for corresponding to such a change is generally performed by a method of regulating an amount of steam generated by the reactor (or a boiler) or regulating an amount of main steam supplied to the turbine.
However, the amount of steam generated by the reactor is regulated by control of a flow rate of the core and position adjustment of the control rod, and the amount of steam generated by the boiler is also regulated by regulating an amount of feed water, an amount of fuel, and an amount of air. Accordingly, a time constant is large until the power of the generator is changed. Therefore, there is a problem in that follow-up performance corresponding to a power change is deteriorated.
The method of regulating the amount of main steam supplied to the turbine through the main steam pipe control valve may merely reduce the power of the generator by reducing an amount of steam supplied to the high-pressure turbine. Accordingly, there is a problem in that, when power of the generator is reduced, the method may not properly correspond to a request for compensation of the reduced power.